The main study objective was to collect implant retrieval information in 10 patients using Vantas®, the 50 mg histrelin implant. Patients who had been identified as having a difficult to locate or non-palpable implant were to have been enrolled. Sites were to adhere to the instructions in the Package Insert, which included specialized investigations such as ultrasound, CT, and MRI, to be used for the location and removal of implants.